![Page 1: Web Science Course 2019 Social networks · Papers (2) • Jure Leskovec, Daniel Huttenlocher, Jon Kleinberg: Signed networks in social media. CHI 2010: 1361-1370. • Jérôme Kunegis,](https://reader033.vdocument.in/reader033/viewer/2022050209/5f5bc72db3b5ac15ff358a64/html5/thumbnails/1.jpg)
Web Science Course 2019Social networks
Philipp Kemkes
1
* Figures from Easley and Kleinberg 2010 (http://www.cs.cornell.edu/home/kleinber/networks-book/)
![Page 2: Web Science Course 2019 Social networks · Papers (2) • Jure Leskovec, Daniel Huttenlocher, Jon Kleinberg: Signed networks in social media. CHI 2010: 1361-1370. • Jérôme Kunegis,](https://reader033.vdocument.in/reader033/viewer/2022050209/5f5bc72db3b5ac15ff358a64/html5/thumbnails/2.jpg)
What is a Social Network ?
• Entities (persons, companies, organizations)• Connections between entities (friendship,
collaboration)
2
![Page 3: Web Science Course 2019 Social networks · Papers (2) • Jure Leskovec, Daniel Huttenlocher, Jon Kleinberg: Signed networks in social media. CHI 2010: 1361-1370. • Jérôme Kunegis,](https://reader033.vdocument.in/reader033/viewer/2022050209/5f5bc72db3b5ac15ff358a64/html5/thumbnails/3.jpg)
Example 1: Karate Club
3
![Page 4: Web Science Course 2019 Social networks · Papers (2) • Jure Leskovec, Daniel Huttenlocher, Jon Kleinberg: Signed networks in social media. CHI 2010: 1361-1370. • Jérôme Kunegis,](https://reader033.vdocument.in/reader033/viewer/2022050209/5f5bc72db3b5ac15ff358a64/html5/thumbnails/4.jpg)
Example 2: Communication in Organization (HP)
4
![Page 5: Web Science Course 2019 Social networks · Papers (2) • Jure Leskovec, Daniel Huttenlocher, Jon Kleinberg: Signed networks in social media. CHI 2010: 1361-1370. • Jérôme Kunegis,](https://reader033.vdocument.in/reader033/viewer/2022050209/5f5bc72db3b5ac15ff358a64/html5/thumbnails/5.jpg)
Example 3: Medieval Trading in Europe
5
![Page 6: Web Science Course 2019 Social networks · Papers (2) • Jure Leskovec, Daniel Huttenlocher, Jon Kleinberg: Signed networks in social media. CHI 2010: 1361-1370. • Jérôme Kunegis,](https://reader033.vdocument.in/reader033/viewer/2022050209/5f5bc72db3b5ac15ff358a64/html5/thumbnails/6.jpg)
Example 4: World Wide Web (Blogs on Presidental Election in 2004)
6
![Page 7: Web Science Course 2019 Social networks · Papers (2) • Jure Leskovec, Daniel Huttenlocher, Jon Kleinberg: Signed networks in social media. CHI 2010: 1361-1370. • Jérôme Kunegis,](https://reader033.vdocument.in/reader033/viewer/2022050209/5f5bc72db3b5ac15ff358a64/html5/thumbnails/7.jpg)
Research Questions
• How do social networks form and how can we model the structure of Social Networks?
• How does information and innovation propagate in Social Networks?
• How do diseases propagate in Social Networks?• How does trade and buisiness work in Social
Networks? • How to detect communities within Social Networks? • ….
7
![Page 8: Web Science Course 2019 Social networks · Papers (2) • Jure Leskovec, Daniel Huttenlocher, Jon Kleinberg: Signed networks in social media. CHI 2010: 1361-1370. • Jérôme Kunegis,](https://reader033.vdocument.in/reader033/viewer/2022050209/5f5bc72db3b5ac15ff358a64/html5/thumbnails/8.jpg)
Topics of this Lecture
• Homophily and Segregation• Friends and Foes• The Small World Phenomenon
8
![Page 9: Web Science Course 2019 Social networks · Papers (2) • Jure Leskovec, Daniel Huttenlocher, Jon Kleinberg: Signed networks in social media. CHI 2010: 1361-1370. • Jérôme Kunegis,](https://reader033.vdocument.in/reader033/viewer/2022050209/5f5bc72db3b5ac15ff358a64/html5/thumbnails/9.jpg)
PART I: Homophily and Segregation
9
![Page 10: Web Science Course 2019 Social networks · Papers (2) • Jure Leskovec, Daniel Huttenlocher, Jon Kleinberg: Signed networks in social media. CHI 2010: 1361-1370. • Jérôme Kunegis,](https://reader033.vdocument.in/reader033/viewer/2022050209/5f5bc72db3b5ac15ff358a64/html5/thumbnails/10.jpg)
Properties of Nodes and Homophily
• Properties: age, gender, education, location, profession, political opinion, …
• Homophily: Similar nodes are more likely to form links.
• Reasons for homophily: – Selection of similar persons as contacts– Becoming more similar to contacts
10
![Page 11: Web Science Course 2019 Social networks · Papers (2) • Jure Leskovec, Daniel Huttenlocher, Jon Kleinberg: Signed networks in social media. CHI 2010: 1361-1370. • Jérôme Kunegis,](https://reader033.vdocument.in/reader033/viewer/2022050209/5f5bc72db3b5ac15ff358a64/html5/thumbnails/11.jpg)
Example: School Network
11
![Page 12: Web Science Course 2019 Social networks · Papers (2) • Jure Leskovec, Daniel Huttenlocher, Jon Kleinberg: Signed networks in social media. CHI 2010: 1361-1370. • Jérôme Kunegis,](https://reader033.vdocument.in/reader033/viewer/2022050209/5f5bc72db3b5ac15ff358a64/html5/thumbnails/12.jpg)
Segregation Example: Chicago
12
![Page 13: Web Science Course 2019 Social networks · Papers (2) • Jure Leskovec, Daniel Huttenlocher, Jon Kleinberg: Signed networks in social media. CHI 2010: 1361-1370. • Jérôme Kunegis,](https://reader033.vdocument.in/reader033/viewer/2022050209/5f5bc72db3b5ac15ff358a64/html5/thumbnails/13.jpg)
Segregation: Schelling Model (1)
13
![Page 14: Web Science Course 2019 Social networks · Papers (2) • Jure Leskovec, Daniel Huttenlocher, Jon Kleinberg: Signed networks in social media. CHI 2010: 1361-1370. • Jérôme Kunegis,](https://reader033.vdocument.in/reader033/viewer/2022050209/5f5bc72db3b5ac15ff358a64/html5/thumbnails/14.jpg)
Segregation: Schelling Model (2)
14
![Page 15: Web Science Course 2019 Social networks · Papers (2) • Jure Leskovec, Daniel Huttenlocher, Jon Kleinberg: Signed networks in social media. CHI 2010: 1361-1370. • Jérôme Kunegis,](https://reader033.vdocument.in/reader033/viewer/2022050209/5f5bc72db3b5ac15ff358a64/html5/thumbnails/15.jpg)
Segregation: Schelling Model (3)
15
![Page 16: Web Science Course 2019 Social networks · Papers (2) • Jure Leskovec, Daniel Huttenlocher, Jon Kleinberg: Signed networks in social media. CHI 2010: 1361-1370. • Jérôme Kunegis,](https://reader033.vdocument.in/reader033/viewer/2022050209/5f5bc72db3b5ac15ff358a64/html5/thumbnails/16.jpg)
Segregation: Schelling Model (5)
16
![Page 17: Web Science Course 2019 Social networks · Papers (2) • Jure Leskovec, Daniel Huttenlocher, Jon Kleinberg: Signed networks in social media. CHI 2010: 1361-1370. • Jérôme Kunegis,](https://reader033.vdocument.in/reader033/viewer/2022050209/5f5bc72db3b5ac15ff358a64/html5/thumbnails/17.jpg)
Segregation: Schelling Model (4)
17
![Page 18: Web Science Course 2019 Social networks · Papers (2) • Jure Leskovec, Daniel Huttenlocher, Jon Kleinberg: Signed networks in social media. CHI 2010: 1361-1370. • Jérôme Kunegis,](https://reader033.vdocument.in/reader033/viewer/2022050209/5f5bc72db3b5ac15ff358a64/html5/thumbnails/18.jpg)
PART II: Friends and Foes
18
![Page 19: Web Science Course 2019 Social networks · Papers (2) • Jure Leskovec, Daniel Huttenlocher, Jon Kleinberg: Signed networks in social media. CHI 2010: 1361-1370. • Jérôme Kunegis,](https://reader033.vdocument.in/reader033/viewer/2022050209/5f5bc72db3b5ac15ff358a64/html5/thumbnails/19.jpg)
Positive and Negative RelationshipsNegative Relationships: – “Real Life”: people you don’t like, rivals, enemies– Online: Slashdot, Epinions– Economy: competitors– Countries: enemies
19
-
--
-
-
-
+
+
+
+
![Page 20: Web Science Course 2019 Social networks · Papers (2) • Jure Leskovec, Daniel Huttenlocher, Jon Kleinberg: Signed networks in social media. CHI 2010: 1361-1370. • Jérôme Kunegis,](https://reader033.vdocument.in/reader033/viewer/2022050209/5f5bc72db3b5ac15ff358a64/html5/thumbnails/20.jpg)
Structural Balance
20
Balanced Unbalanced
![Page 21: Web Science Course 2019 Social networks · Papers (2) • Jure Leskovec, Daniel Huttenlocher, Jon Kleinberg: Signed networks in social media. CHI 2010: 1361-1370. • Jérôme Kunegis,](https://reader033.vdocument.in/reader033/viewer/2022050209/5f5bc72db3b5ac15ff358a64/html5/thumbnails/21.jpg)
Weak Structural Balance .
21
Balanced Unbalanced
![Page 22: Web Science Course 2019 Social networks · Papers (2) • Jure Leskovec, Daniel Huttenlocher, Jon Kleinberg: Signed networks in social media. CHI 2010: 1361-1370. • Jérôme Kunegis,](https://reader033.vdocument.in/reader033/viewer/2022050209/5f5bc72db3b5ac15ff358a64/html5/thumbnails/22.jpg)
Structural Balance: Global Consequences
22
![Page 23: Web Science Course 2019 Social networks · Papers (2) • Jure Leskovec, Daniel Huttenlocher, Jon Kleinberg: Signed networks in social media. CHI 2010: 1361-1370. • Jérôme Kunegis,](https://reader033.vdocument.in/reader033/viewer/2022050209/5f5bc72db3b5ac15ff358a64/html5/thumbnails/23.jpg)
Weak Structural Balance• In addition to triangles in Structural Balance: – Allow: triangles with 3 negative edges
• Global consequences:
23
![Page 24: Web Science Course 2019 Social networks · Papers (2) • Jure Leskovec, Daniel Huttenlocher, Jon Kleinberg: Signed networks in social media. CHI 2010: 1361-1370. • Jérôme Kunegis,](https://reader033.vdocument.in/reader033/viewer/2022050209/5f5bc72db3b5ac15ff358a64/html5/thumbnails/24.jpg)
Further Generalizations
• Incomplete networks: Structural Balance can be extended to complete balanced network by adding signed edges
• Approximate Balanced Networks: Balance property can be violated for fraction of triangles
24
![Page 25: Web Science Course 2019 Social networks · Papers (2) • Jure Leskovec, Daniel Huttenlocher, Jon Kleinberg: Signed networks in social media. CHI 2010: 1361-1370. • Jérôme Kunegis,](https://reader033.vdocument.in/reader033/viewer/2022050209/5f5bc72db3b5ac15ff358a64/html5/thumbnails/25.jpg)
International Relations
25
![Page 26: Web Science Course 2019 Social networks · Papers (2) • Jure Leskovec, Daniel Huttenlocher, Jon Kleinberg: Signed networks in social media. CHI 2010: 1361-1370. • Jérôme Kunegis,](https://reader033.vdocument.in/reader033/viewer/2022050209/5f5bc72db3b5ac15ff358a64/html5/thumbnails/26.jpg)
PART III: The Small World Phenomenon
26
![Page 27: Web Science Course 2019 Social networks · Papers (2) • Jure Leskovec, Daniel Huttenlocher, Jon Kleinberg: Signed networks in social media. CHI 2010: 1361-1370. • Jérôme Kunegis,](https://reader033.vdocument.in/reader033/viewer/2022050209/5f5bc72db3b5ac15ff358a64/html5/thumbnails/27.jpg)
Small World and „Six Degrees of Separation“
• Small Word Phenomenon: Paths connecting two people in a social network are short(Pop Culture: „Six Degrees of Separation“)
• Milgram Experiment (1960s): – Ask set of „starters“ to forward a letter to „target“
person– „starters“ are given some information, e.g. address,
occupation– Rule: forward letter to person‘s you know on a first-
name basis
27
![Page 28: Web Science Course 2019 Social networks · Papers (2) • Jure Leskovec, Daniel Huttenlocher, Jon Kleinberg: Signed networks in social media. CHI 2010: 1361-1370. • Jérôme Kunegis,](https://reader033.vdocument.in/reader033/viewer/2022050209/5f5bc72db3b5ac15ff358a64/html5/thumbnails/28.jpg)
Small Word Phenomenon
28
![Page 29: Web Science Course 2019 Social networks · Papers (2) • Jure Leskovec, Daniel Huttenlocher, Jon Kleinberg: Signed networks in social media. CHI 2010: 1361-1370. • Jérôme Kunegis,](https://reader033.vdocument.in/reader033/viewer/2022050209/5f5bc72db3b5ac15ff358a64/html5/thumbnails/29.jpg)
Milgram Experiment: Results
29
![Page 30: Web Science Course 2019 Social networks · Papers (2) • Jure Leskovec, Daniel Huttenlocher, Jon Kleinberg: Signed networks in social media. CHI 2010: 1361-1370. • Jérôme Kunegis,](https://reader033.vdocument.in/reader033/viewer/2022050209/5f5bc72db3b5ac15ff358a64/html5/thumbnails/30.jpg)
Small World: MS Instant Messenger
30
![Page 31: Web Science Course 2019 Social networks · Papers (2) • Jure Leskovec, Daniel Huttenlocher, Jon Kleinberg: Signed networks in social media. CHI 2010: 1361-1370. • Jérôme Kunegis,](https://reader033.vdocument.in/reader033/viewer/2022050209/5f5bc72db3b5ac15ff358a64/html5/thumbnails/31.jpg)
Seminar Papers
31
![Page 32: Web Science Course 2019 Social networks · Papers (2) • Jure Leskovec, Daniel Huttenlocher, Jon Kleinberg: Signed networks in social media. CHI 2010: 1361-1370. • Jérôme Kunegis,](https://reader033.vdocument.in/reader033/viewer/2022050209/5f5bc72db3b5ac15ff358a64/html5/thumbnails/32.jpg)
Papers (1)
• Avery Ching, Sergey Edunov, Maja Kabiljo, Dionysios Logothetis, and Sambavi Muthukrishnan. One trillion edges: graph processing at Facebook-scale. VLDB 2015: 425-443
• Jure Leskovec, Eric Horvitz: Planetary-scale views on a large instant-messaging network. WWW 2008: 915-924.
32
![Page 33: Web Science Course 2019 Social networks · Papers (2) • Jure Leskovec, Daniel Huttenlocher, Jon Kleinberg: Signed networks in social media. CHI 2010: 1361-1370. • Jérôme Kunegis,](https://reader033.vdocument.in/reader033/viewer/2022050209/5f5bc72db3b5ac15ff358a64/html5/thumbnails/33.jpg)
Papers (2)
• Jure Leskovec, Daniel Huttenlocher, Jon Kleinberg: Signed networks in social media. CHI 2010: 1361-1370.
• Jérôme Kunegis, Andreas Lommatzsch, Christian Bauckhage: The slashdot zoo: mining a social network with negative edges. WWW 2009: 741-750.
33
![Page 34: Web Science Course 2019 Social networks · Papers (2) • Jure Leskovec, Daniel Huttenlocher, Jon Kleinberg: Signed networks in social media. CHI 2010: 1361-1370. • Jérôme Kunegis,](https://reader033.vdocument.in/reader033/viewer/2022050209/5f5bc72db3b5ac15ff358a64/html5/thumbnails/34.jpg)
Thank you.
Questions?
34